This study investigates the complex interactions between acoustic pressure and mass diffusion in a non-local polymer composite thermoelastic medium subjected to a thermal laser source (laser pulse), analyzed using normal mode analysis. The focus is on understanding the coupled effects of thermal, mechanical, and chemical actions within the medium. The thermal laser source induces thermal waves that interact with the thermoelastic and diffusive properties of the material. The analysis reveals that acoustic pressure influences the mass diffusion process through a chemically potential mechanism, which in turn affects the overall thermoelastic response of the composite. The non-local theory accounts for the microstructural effects, more accurately representing the material behavior under thermal loading. Numerical simulations demonstrate the significance of non-local effects and chemical reactions on the coupled field interactions, highlighting their impact on the stability and performance of polymer composites in advanced engineering applications.